Users browsing Internet web sites may encounter pop-up or pop-under windows. A pop-up window may contain unsolicited advertisements intended to attract web traffic or capture information from the user, such as email addresses or browsing preferences. Pop-up ads may be in the form of new web browser windows generated or launched by the web site and displayed above the web browser. Pop-up ads may also be in the form of an overlay of the web site, in which content is obscured by the overlay. Pop-under windows are a variation of pop-up windows, where a new window browser window is open or launched beneath the active browser window.